Perforating die and stripping mechanism therefor



Jan. 1, 1935. L. v. WHisTLER 1,986,036

VPERFORATING DIE ANDSTRIPPI'NGMECHANIISII THEREFOR Filed Oct. 25, 1932Patented Jan. 1', 1935 .rnnroaarmd- DIE AND s'mmrma MECH- ANISMTHEREFOR- Lawrence V. Whistler, Kenmore, N. Y., assignor to S. B.Whistler 8; Sons, sine Buffalo, N. I, a I

corporation of New York Application October 25, 1932, Serial No. 639,447

2 Claims.

My invention relates to perforating dies and stripping mechanismtherefor; also to the mannor of securing the same to metal working orother similar presses.

One of the objects of my invention is theprovision of perforating dieswhich are adiustably secured to press platens, such as the ram and bedmembers of a press, and in which new and novel means are provided for sosecuring them in any position in the areas of said platens.

Another object of my invention is the provision of novel means forretaining the female member of a set of perforating dies on a platen,

and to provide new and novel stripping means whereby sheet metal orother material perforated by the dies is stripped from the perforatingpunch or male members "-Another object ,of my invention is the provisionof new and novel porforating punches and means for retaining them inposition, said perforating punches'being conveniently removable from thepress platen so that others may be substituted therefor.

Another object of the invention is the provision of a stripperelement ona perforating punch spring-retained in position by the use of;

a cushioning element adapted to be compressed,

' or more fully compressed, under operation of the press. I

A further object of my invention is the provision of punch elementsadapted to be interchangeably secured to a press platen, each punchelementhaving a helical spring surrounding it within a cage havingspace-apart elements relatively movable, one of said spaced elementsbeing secured to the punch element and the other maintained in positionby means of said helical spring and suitable connector elementsconnecting said spaced-apart elements together.

A still further object of my vention is the provision of a stripperdevice detachably secured to a perforating punch and comprising a cagesecured to said punch and extensible and contractible thereon, and ahelical spring enclosed within said cage to normally hold the same inextended position and to permit of contracting said cage under pressureapplied thereto during perforating action of 'the press.

A still further object of my invention is the provision of punch holdersapplied to a platen of a press, perforating punches interchangeablysecurable to the punch holders, and a. stripper device removably appliedto the perforating punch in use.

With the above and other objects in v'et" to appear hereinafter, myinvention consists in the novel features of construction and in thearrangement and combination of parts to be hereinafter described andmore particularly pointed ES PATENT. OFFICE:

similar press, saidhplatens being equipped with.

perforating or punching dies and a stripper device representative of myinvention.

Fig. 2 is a bottom plan view of a portion of the upper press platen soequipped. I

Fig. 3 is a central longitudinal section of my improved stripper deviceillustrated as a complete unit and detached from the perforating punch.I

Fig. 4 is a top plan view of said device.

Fig. 5 is a sectional view of a centering device used temporarily inconnection with atemplet perforated to assure proper location on theplaten of the female member of a pair of perforating dies.

platen, showing one of the material gages.

Reference being had to the drawing in detail,

the numeral 6 designates the upper platen of a metal-working or othersimilar press, and 7 the lower platen thereof. In each of these platens,I

parallel bolt retainer grooves 8 are formed; these being shown ofT-formation, but they may be otherwise formed.

Secured to the under side of the upper platen is a punch holder orretainer 9 into which the male member or perforating punch 10 of a pairof perforating dies is secured. This punch holder or retainer is in theform of a bar 11 provided with a longitudinal slot 12 and having atoneend a head or enlargement 13 extending downwardly therefrom, saidhead being axially bored out, as

at 14, and having a counterbore or depression 15 Fig. 6 is a plan viewof a portionof the lower in shape. In the drawing I have shown aperforating punch whose lower portion is somewhat reduced in diameterand of cylindrical formation so that it will serve to punch a, roundopening of definite size in a sheet of metal or other material. Thislower portion may, however, be reduced,- twice in diameter from itsenlarged upper or securing Portion, and may also have its lower or punchend of any desired shape in cross section, depending onthe particular'shapeof the opening to be punched in the material.

It will be apparent therefore that punches of various shapes anddiameters are adapted to be used in connection with the punch holder orretainer 9; and in all instances'the punches used in said holder orretainer have their upper or securing portions of a shape and sizeconforming to the bore 14 of said holder 'or retainer while.

their lower portions may be varied and be of different diameters orthicknesses along their length *Y-shaped grooves while the shankportions of the bolts adjacent said heads are entered into the vertical,or narrow portions of said-grooves, the remaining portions of the shanksof said bolt or bolts being passed through the slot 12 in the punchholder or retainer. These bolts have nuts 17 applied thereto which bearagainst washers 18 placed against the punch holder or retainer. Thesepunch holders or retainers may be adjusted lengthwise, or rotated on oneof said bolts while sliding the other bolt in its retainer groove andvarying the position thereof in the slot of the punch holder; or, when asingle bolt is used, the punch holder may be rotated on the bolt so asto assume any angular position desired. In this manner a punch heldwithin said punch holder or retainer may be positioned at any desiredpoint within the area of the platen. In some instances the bar 11 ispositioned at a right angleto the T-shaped grooves in the platen, inother instances parallel thereto, and it may be positioned at anydesired. angle with respect to said T-shaped grooves.

Positioned within the counterbore or depression 15 of the punch holderor retainer is a hardened wearing plate 19, it being backed-up by theplaten and being adapted to have the upper end of the perforating punch10 bear thereagainst.

I Each perforating punch is notched, as at 20, the notch being ofsubstantially V-formation and extending across the peripheral surface ofthe upper or securing portion. of the punch. Both walls ofeach notch aretherefore obliquely disposed and into the head or enlargement 13 of thepunch holder or retainer 9. securing screw 21 is threaded, a tappedscrew opening being provided for said securing screw and extendingfrom'the outer face of said head or enlargement inwardly obliquely tothe bore 14 therein, the axis 'of said tapped screw opening beingpreferably parallel with one of the walls of the V-shaped notch in theperforating punch and at right angles to the other all thereof.

The securing screw 21 has its inner end por-- tion reduced in diameter,as at 22, and this reduced portion is smooth surfaced or unthreaded andadapted to be entered into the V-shaped notch of the punch so as to bearagainst the upper or contact wall portionof said notch. The

perforating punch is thus securely. held within the punch holder orretainer and can be quickly and easily removed therefrom when it isdesired to replace it with another; it being simply necessary tounthread the screw 21 so as to cause the inner smooth surfaced endportion of registrars" to recede fully into the tapped screw opening inthe head of the punch holder or retainer.

I preferably continue the diameter of the upper or securing portion ofthe punch downwardly a distance below the head or enlargement 13 of thepunch holder or retainer and secure thereto a stripper device,designated as a whole by the numeral 23. This device is in the form of acage and comprises an upper member or header 24, a lower member orheader 25, a circular series of guides 26 on which said members arerelatively movable towards and away from the other, and a helical springor other cushioning element 27 interposed between said upper and lowermembers or headers and surrounded by said circular series 'of guides.The upper member or header 24, which may also be referred to as asecuring member or header, has a radially-disposed tapped opening formedtherein into which a securing screw 28 is threaded, which firmly bearsagainst the perforating punch 10 axially entered in the upper member orheader and securely fastens said member or header'to the punch. The saidheader is provided on its under side with a central downwardly-openingdepression or pocket 29, and it is peripherally notched, as at 30, thenotches extending from the upper face of said header downwardly to aplane within a short distance of the lower face thereof so as to providestop lugs 31, for a purpose to presently appear, 30

said stop lugs forming the lower walls of said notches. These stop lugsare provided with smooth-surfaced bolt holes 32 and axially alinedtherewith are bolt holes 33 which are formed in the lower member orheader 25 of the stripper 35 device. The guides 26 are in the form ofrods, and more particularly considered, screw bolts having their headsnormally entered in the notches 30 and bearing against the upper facesof the stop lugs 31 in the upper member or header, while their lowerextremities are screw-threaded and entered into the tapped bolt holes 33in the lower member or header 25. I

The helical spring 27 is interposed between the two members or headers,as stated, and surrounds the perforating punch, the upper end of this vspring being entered into the depression or pocket 29 in the uppermember or header and it has its lower end bearing against the upper faceof the lower member or header 25. The lower member or header 25 has anaxial opening 34 therein into which, or through which, the lower orpunch end of the perforating, punch is passed; the arrangement beingpreferably such that the punch end of said punch terminotes within saidopening. Wabbling of the lower member or header 25 is therefore avoided,and

assurance of movement of said header in a perfectly vertical directionassured.

The helical spring is normally 'under slight 60 compression so as toexert pressure against the lowQr; member or header 25 of thestripperdevice and cause the heads of the guides orguide bolts 36 tobear against the lugs 31 of the upper member or header 24.

approximatesthat of or is of greater diameter than the head orenlargement 13 of the punch holder or retainer. For the purpose ofincreasing the accessibility of a tool to the securing screw 21, I findit of advantage to notch or cut away the head or enlargement 13 of thepunch holder or retainer, as at 35, directly over a notch 20 in theupper member or head 24 of the stripper device, said notch or cut-awayportion facing downwardly and outwardly.

A die retainer 36 isapplied to the lower platen '7 of the press and thiscomprises a bar 3'1 providedwith alongitudinal slot 38 and having at oneend an upstanding head 39, cupped at its upperv endto receive a femaledie 40 provided with an axial opening 41, which is preferably'downwardly flared and the upper end of which is of a diameter or sizeand also of a shape to conform to the lower effective punch end-of theperforating punch 10. This upstanding head has an opening 42 extendingfrom the female die 40 downwardly and outwardly to the side of the headso that material punched out of a sheet of metal or the like, designatedby the numeral43 and lying upon the female die, may, be directed throughsaid die and through said opening and be deposited on the lower platen,from which it may be removed, as and when desired.

Securing bolts 44 are entered into the T-shaped retainer. grooves of thelower platen in the manner in which the securing bolts 16 are enteredinto the bolt-retainer grooves of the upper platen, and these bolts arepassed through the slot 38 of the die retainer. Nuts and washers formingpart of said bolts serve to securely fasten the die retainer to thelower platen in the same manner as the nuts and washers 17 and 18,respectively, employed to secure the punch holder or retainer to theupper platen.

The sheet of metal or other material is positioned in contact-with oneor more gages 45, one of which only is shown fastened to the lowerplaten and extends upwardly therefrom; but, if desired, these may befastened to the upper platen and extend downwardly therefrom. Thesegages are spaced apart along at least one dimen-' sion of a platen andeach comprises an angular structure having a horizontal arm 46, slottedas at 47, and a vertical arm 48, which is an upstanding arm in theapplication illustrated.

Securing bolts 49 are entered in the bolt-retaining grooves 8 of thelower platen in the same manner as the securing bolts 16 and 44, andthese are passed through the slots in the horizontal arms 46 of thegages, washers and nuts forming part of such bolts being employed totighten the gages to the platen.

By trending the T-shaped retainer grooves in one directionand inparallel relation, the perforating dies may be secured to the platens inco-axial alinement and at any desired points in the areas of saidplatens; the position of these dies depending on theexact location theperforations are to be formed in the sheet metal or other material to bepunched or perforated.

Prior'to commencing the punching or per-,

forating operation it is necessary to ascertain the exact points oflocation of the die members on the platens, and this is accomplished bypositioning the gages on one or the other of the platens and placing ation-locating or centering openings therein against the gages.Preparatory thereto, however, the die retainer 36 is loosely positionedupon the lower platen, it'having been provided with a centering plug 50shown in Fig. 5. This/plug is fitted into the upstanding head 39 of thedie templet having small posiretainer and extending axially therefrom inan upward direction is a centering point 51 which is adapted to fit thesmall position-locating or centering opening of the templet. The dieretainer isthen moved into such position on the platen that thiscentering point will be positioned in the opening of the templet whilethe latter is held against the gages, after which the bolts 44 ofthe dieretainer are. tightened. The templet is centering plug from the dieretainer, and the proper female die member inserted in the die retainer..The male die or punch element, hereinafter referred to as theperforating punch, is then po- 15.

ated upon is inserted into the press to assume the position shown inFig. 1, after which the upper platen is lowered to cause the stripperproper or lower member or surface of the material. This causes thespring 27 of the stripper device to be compressed and the guide bolts 26to travel upwardly in theopenings 32 of the upper member or header 24 ofthestripper device, the heads of said moving awayfrom the stop lugs 31formed on said'uppe'r member or header. Simultaneously therewith theperforating punch 10 is lowered. and pressed through the metal or othermaterial so as" to enter the female die member 40, with the die memberand from the opening which it formed in the sheet metal or 0 hermaterial, and as said punch becomes released from the sheet metal thestripper element 25 remains momentarily in contact with the metal underthe expansive force then removed from the machine, the If) a): The sheetmetal or other material to be operheader-25 to engage the upper 2,5

uide .bolts 9':

of thespring 2"luntil this force causes the guide bolts 26 to be movedto normal position with their heads in contact with the stop lugs 31,after which the continued upward movement of the upper platen of the,press will cause said stripper element to be moved out of engagementwith the sheet metal or othermaterial-so that this material, properlyoperated upon, can be freely withdrawn from themachine.

The stripper device, comprising the two head-' ers 24 and 25, thehelical spring 2'1, bolts 26, therefore hold the sheet metal or othermaterial being punched or perforated in contact" with the female diemember, until after the punch is fully withdrawn from said material.

For the purpose of clearness I distinguish between the stripper deviceasan entirety and the a stripper or stripper element 25 in that I considerthe element brought into direct and actual-contact with ,the materialoperated upon to be the stripper proper,-while this element associatedwith other parts form the complete stripper device, which is removableas a unit from the perforating punch.

when a hole larger or smaller is required than that which theperforating punch will make, or a hole which is of different formation,the perforating punch is removed from the punch holder or retainer 9with the stripper device attached thereto; or if desired, the' stripperdevice maybe removed, from the perforating 75 and the guide" 5 in themespunch before removing the pimch from its holder or retainer. A newperforating punch con-.

certain elements of the same stripper device may be employed, as it willonly be necessary that the lower member or header has an axial openingconforming to that of the lower or punch end of the substitutedperforating punch. Replacement of the lower member or element of thestripper device can be easily accomplished by unthreading the guidebolts 26 from the tapped bolt holes 33 in the lower member or header ofthe device and then axially positioning another having a difierent axialopening and threading the guide bolts 26 into the tapped openingsthereof.

While in the drawing I have shown a single set or pair of die members,it is to be understood that a plurality of such sets are oftentimesused,

and that therefore the drawing is merely representative of my inventionand of the use thereof. It will be apparent that in my improved stripperdevice, the spring 27 is confined within an openwork housing or cage,and that in theevent of the spring becoming broken, it will not causedamage to the dies or the material worked upon, sime the broken portionsof the spring will be wholly confined within the housing or cage, andretain its position around .the perforating punch, even thoughineffective in maintaining the stripper proper under spring pressure.

Having thus described my invention, what I claim is: e

1. The combination of a punch retainer secured to a platen and having acut-away portion facing downwardly and outwardly, a punch having one'endremovably fitted in said retainer and having .a peripheral notch thereinpresenting faces at an angle to each other, said faces being 7 bothdisposed obliquely to the axis of said punch,

a'securing screw adjustable within said punch retainer and having itsinner end entered in said peripheral notch and its outer endaccessibleby' way of "said cut-away portion, and a stripper devicesurroimding the lower portion .of said punch and comprising an upperheader secured to said punch directly beneath said punch retainer andhaving a peripheral notch in vertical alinement with the cut-awayportion of said punch retainer, guide rods slidably fitted in said upperheader ,and having enlargements normally bearing against said header, alower header into which the lower ends of said guide rods are securedand having an axial opening into which the lower portion of said punchis slidably fitted, and a helical spring interposed between said headersaround said punch.

2. A punch retainer having a cut-away portion facing downwardly andoutwardly, a punchhaving one end fitted in said retainer and having aperipheral notchat said end, a securing screw threaded into said punchretainer and havingits inner end entered within said peripheral notchand its outer end accessible by way of said cutaway portion, and astripper device applied to the projecting portion of said-punch andhaving a peripheral notch in vertical alinement with the cut-awayportion of said punch retainer to permit access to said securing screw.

LAWRENCE V. WHISTLER.

